Electromagnetic relays



P. V. LITTLE ELECTROMAGNETIC RELAYS Dec. 23, .1969

Filed Nov. 2'7, 1967 ENTR uak M4 ATTORNEYS v United States Patent3,486,141 ELECTROMAGNETIC RELAY S Philip Vernon Little, Burnley,England, assignor to Joseph Lucas (Industries) Limited, Birmingham,England, a British compan Filed Nov 27, 1967, Ser. No. 685,803 Claimspriority, application Great Britain, Dec. 12, 1966, 55,489/ 66 Int. Cl.H01h 3/00 US. Cl. 335-187 3 Claims ABSTRACT OF THE DISCLOSURE In anelectromagnetic relay there is provided a casing including a base, anelectromagnet housed within the casing and including a coil wound on aformer, an armature carrying a movable contact of the relay, and a fixedcontact engageable by the movable contact. The armature and the fixedcontact are carried by the former on which the coil is wound and theformer has secured thereto a plurality of terminal members which in useextend through slots in the base of the casing, the terminal membershaving resilient parts which are flexed to allow the terminal members topass through the slots in the base of the casing and the parts thenflexing to a position wherein they engage the base to prevent withdrawalof the former and its associated parts from the casing.

This invention relates to electromagnetic relays of the kind comprisinga casing including a base, an electromagnet housed within the casing:and including a coil wound on a former, an armature carrying themovable contact of the relay, and a fixed contact engageable by themovable contact.

According to the invention in a relay of the kind specified the armatureand the fixed contact are carried by the former on which the coil iswound and the former has secured thereto a plurality of terminal memberswhich in use extend through slots in the base of the casing, theterminal members having resilient parts which are flexed to allow theterminals to pass through the slots the parts then flexing to a positionwherein they engage the base to prevent withdrawal of the former fromthe casing.

One example of the invention is illustrated in the accompanying drawingswherein;

FIGURE 1 is a sectional view of an electromagnetic relay,

FIGURE 2 is a sectional view on the line 22 in FIGURE 1 with thearmature and its associated return spring omitted for clarity, and

FIGURE 3 is a view in the direction of arrow A in FIGURE 1.

Referring to the drawings, the relay includes a moulded synthetic resincasing 11 of open box like construction, having a base 12. The coil 13of the relay is housed in the casing 11 and is 'wound on a mouldedformer 14. Secured to the former 14 are two pairs of conductive bladeterminals 15, 16 the terminals 16 each including 'a contact adjacent thecoil 13, while the terminals 15 are connected to the ends of the coil 13respectively.

The core 17 of the relay extends axially through the coil 13 and isparallel to the base 12. Secured to one end of the core 17 is one limbof an L-shaped member 18 the other limb of which extends parallel withthe core 17 and carries at its free end the armature 19 of the relay.The armature 19 extends at right angles to the core 17 and carries atits end remote from the member 18 a bifurcated conductive member 21having integral therewith a pair'of contacts 22. The member 18 includesa part 23 which extends substantially parallel with the armature 19, thepart 23 and the end of the armature 19 remote from the member 21 beinginterconnected by a spring 24.

In order to assemble the relay the terminals 15, 16 are engaged withslots in the base 12, the terminals 15, 16 projecting externally fromthe base for connection to respective leads.

Each of the terminals 15, 16 includes a resilient tag 25 which, as theterminal is engaged with its respective slot, is flexed to allow theterminal to pass through the slot. The tags 25 are so arranged that whenthe former 14 engages the inner surface of the base 12 the tags 25 canflex outwardly to engage the outer surface of the base 12 and therebyprevent withdrawal of the assembly from the casing 11.

The opreation of the relay is as follows:

When the coil 13 is energised the armature 19 is drawn against theaction of the spring 24 towards the core 17 and in so doing moves thecontacts 22 into engagement with the contacts 20 so electricallyinterconnecting the terminals 16 through the member 21, and completing acircuit through the terminals 16. When the coil 13 is deenergised thearmature 19 is returned by the spring 24 so breaking the circuit throughthe terminals 16.

When the coil 13 is de-energised the member 21 engages the wall of thecasing, however in a modification a second pair of contacts are providedadjacent the Wall of the casing 11 and in the de-energised condition ofthe relay the member 21 completes a second electrical circuit throughthe second pair of contacts.

After assembly the open end of the casing 11 is closed by a resilientplate 26 which is snapped into an internal circumferential groove 27 inthe casing 11.

In order to mount the relay in position on, for example a metal plate 29constituting part of a road vehicle, the base 12 has a larger crosssection than the remainder of the casing 11 and is formed with anexternal circumferential groove 28. The casing can then be inserted intoa corresponding hole in the plate 29 and can be snapped into engagementwith the plate, the periphery of the hole engaging the groove 28 in thebase 12. Alternatively the base could be formed with a pair of outwardlydirected lugs with which screws can be engaged to mount the relay in amore conventional manner.

Having thus described my invention what I claim as new and desire tosecure by Letters Patent is:

1. An electromagnetic relay comprising a casing including a base, anelectromagnet housed within the casing and including a coil wound on aformer, an armature carrying the movable contact of the relay, and afixed contact engageable by the movable contact, said armature and thefixed contact being carried by the former on which the coil is wound andthe former having secured thereto a plurality of terminal members whichin use extend through slots in the base of the casing, the terminalmembers having resilient parts which are flexed to allow the terminalsto pass through the slots, the parts then flexing to a position whereinthey engage the base to prevent withdrawal of the former from thecasing.

2. A relay as claimed in claim 1 wherein the former is moulded insynthetic resin.

3. A relay as claimed in claim 1 wherein the casing is adapted to bemounted as a snap fit in an aperture in a panel.

References Cited UNITED STATES PATENTS 4 'Heyhal 20 0-166 Neurnann335-187 Valleau 335-297 Wright 200-166 Zerwic 335-297 BERNARD A.GILHEANY, Primary Examiner H. BROOME, Assistant Examiner

